feat(devex): add a typescript sdk package with a typed ledger client

.github/workflows/sdk-ts-ci.yml

@@ -0,0 +1,34 @@
+name: SDK TypeScript CI
+
+on:
+  push:
+    branches: ["main"]
+    paths: ["sdk/typescript/**", ".github/workflows/sdk-ts-ci.yml"]
+  pull_request:
+    paths: ["sdk/typescript/**", ".github/workflows/sdk-ts-ci.yml"]
+
+concurrency:
+  group: sdk-ts-ci-${{ github.ref }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+
+jobs:
+  sdk-ts:
+    name: TypeScript SDK build & test
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: sdk/typescript
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: "22"
+          cache: npm
+          cache-dependency-path: sdk/typescript/package-lock.json
+      - run: npm ci
+      - run: npm run typecheck
+      - run: npm run test
+      - run: npm run build

sdk/typescript/.gitignore

@@ -0,0 +1,2 @@
+node_modules/
+dist/

sdk/typescript/README.md

@@ -0,0 +1,18 @@
+# @fincore/sdk-typescript
+
+A typed `fetch` client over the FinCore Engine REST API. Isomorphic (works in Node 18+ and browsers via the global `fetch`), with no runtime dependencies.
+
+```ts
+import { FincoreClient } from '@fincore/sdk-typescript'
+
+const client = new FincoreClient({ baseUrl: 'http://localhost:8080', token: '<jwt>' })
+
+const page = await client.listAccounts()
+const account = await client.getAccount(page.items[0].id)
+```
+
+A non-2xx response throws `FincoreError` carrying the HTTP `status`. The bearer token is sent only when provided.
+
+The current surface covers the ledger account reads; further operations are tracked as follow-ups. This package is not published to a registry.
+
+SPDX-License-Identifier: BUSL-1.1